Equipment for circular knitting machines



Oct. 5, 1965 J. A. SHARP ETAL 3,209,559

EQUIPMENT FOR CIRCULAR KNITTING MACHINES Filed March 4, 1963 4 Sheets-Sheet l Oct. 5, 1965 J. A. SHARP ETAL EQUIPMENT FOR CIRCULAR KNITTING MACHINES 4 Sheets-Sheet 2- F'iled March 4, 1963 4 Sheets-Sheet 5 J in Oct. 5, 1965 J. A. SHARP ETAL EQUIPMENT FOR CIRCULAR KNITTING MACHINES Filed March 4, 1965 Oct. 5, 1965 J. A. SHARP ETAL 3,209,559

EQUIPMENT FOR CIRCULAR KNITTING MACHINES Filed March 4, 1963 4 Sheets-Sheet 4 III O r 22 17 30 ll 2 .29 'ul 2O 13 25 fax United States Patent Ofiice 13,29,559 Patented Get. 5, 1965 3,209,559 EQUIPMENT FOR CIRCULAR KNITTING MACHINES Joseph A. Sharp and Desmond L Jinks, Leicester, England, assignors to N. Corah (St. Margaret) Limited, Leicester, England, a company of Great Britain Filed Mar. 4, 1963, Ser. No. 262,679 Claims priority, application Great Britain, Mar. 16, 1962, 10,076/6'2 7 Claims. '(Cl. 66147) This invention relates to circular knitting machines and is concerned with equipment thereon intended for the cutting into lengths of knitted material continuously produced on such machines. This cutting into lengths is required in more than one situation-as will become apparent to the reader as this specification develops. To cite one example, the knitted material may be continuously-produced tubular body fabric in the piece which must be cut up into sections of length for use.

Another example is the string of garments, e.g. socks, which comes down with loose courses between the individual garments, from which these individual articles have eventually to be separated at the loose courses. This latter case is, in fact, a very apt example and attention will be focussed on it in the ensuing specification to facilitate and clarify the exposition of the invention.

These strips, e.g. of half hose or socks, are normally taken down in the machine and individually separated away from the latter-usually by hand. An object of the present invention is to enable the individual pieces (garments or lengths) to be separated from one another on the knitting machine and whilst the latter is knitting and the take down continues.

A further object is an arrangement which will guarantee a precisely-timed and efiicient cutting operation.

With these aims in view, we provide in or for a knitting machine an arrangement for severing individual lengths from a continuously knitted parent length of knitted material (hereinafter referred to as the work), comprising a severing device disposed adjacent the path of travel of said work and means responsive to this travel to cause said severing device to act on the work whilst the travel of the latter continues.

The separated individual pieces may be collected or may be dropped into a conveying system for automatic transfer through the system, for example for sorting or delivery to a selected destination.

In a preferred arrangement the travel-responsive means includes a device for scanning the passing work and a severing device operating means which are adapted to be triggered by the scanning device in response to the detection of a significant feature in the work to bring the severing device into action. The feature referred to may be of various forms, and the scanning means chosen according to the particular nature of this feature. For example, as will be later described, a changing amount of the knitted yarn itself may be used to operate the scanning means, and this consequently may be of a lightresponsive type.

In pursuance of this latter arrangement the successive individual courses may be connected in the work by loose knitted courses, which will be more easily light permeable than the remainder of the knitted fabric, and a scanning device in the form of a photo-electric unit may be used and positioned to detect the loose courses in the passing work. This system is, for instance, particularly applicable in the case of the knitting of strings of socks or half hose referred to above, where the successive individual items may be knitted off the machine joined by loose courses of alginate thread.

Where a scanning device is utilised for the purpose indicated, it will be of advantage if the travel-responsive means further includes a control assembly, operable at intervals in timed relation with the knitting controls of the machine, to prepare the scanning device. This set-up, which is simple to implement in the case of standard circular knitting machines having a main control drum or equivalent, is based on the principle that it can be used as a safety means to ensure that the scanning device is only brought into effective use at appropriate periods, although it itself selects the final moment to perform the severing operation. This has, inter alia, the great advantage that the scanning unit will be in no danger of being triggered, to bring the severing device into operation inadvertently, by a false reading of the work, for example of some other part thereof which is normally more light permeable than the remainder or may be otherwise susceptible to detection.

Standard forms of circular knitting machine usually include take-down means in the form of a pair of cooperating rollers which are intermittently rotated together, to pull the work down in the nip between them, under the control of the pattern drum of the machine acting through a pattern chain. For convenience of explanation of the invention and to save confusion, we shall hereafter focus attention on this particular type of knitting machine, it being understood that the invention can be used in analogous situations.

The severing device referred to can take various practical forms, for example of a shearing type such as a pair of cutter jaws or a cooperating movable knife and fixed anvil, but it will be appreciated that they will best be arranged close to the exit side of the take-down means or rollers. Not only does this give a compact assembly but allows for a close control of the point of severance Where the work is just leaving and is still gripped by the takedown means. Hence, as will be explained below, the Work can be tensioned by the interaction of the rollers and the severing device, and a positive and accurate cut guaranteed.

Furthermore any movement which the take-down means themselves may normally perform in addition to their purely feeding function may, in accordance with a feature of the invention, be exploited to :assist or implement the cutting action of the severing device. Thus, where the take-down rollers of a machine are reciprocated on the so-called never rest principle, i.e. in a circular arc and transversely to the downward direction of take down travel of the work, this motion can be used to cause the operative swing of a knife edge of the severing device at required times selected by the machine controls.

To illustrate this point in more concrete terms, let it be assumed that the take-down rollers are mounted on a support plate which, in conventional fashion, is rotationally reciprocated by the machine controls during the take down procedure. In this event the severing device may comprise a knife blade which Will be arranged to perform a cutting stroke as a function of this reciprocatory movement, at times dictated by a machine control, eig. the pattern chain.

In implementing this arrangement the knife blade can be pivotally mounted on the support plate and have an abutment piece which will, when a severing operation is to be performed, engage a trip element, brought into position by the machine controls, so as to swing the knife blade relatively to the take-down rollers and the work, and so cut across the latter.

Moreover, to allow for a progressive cutting through of the work, the cooperating sharp edges of the anvil and movable knife blade will preferably be curved, e.g. in a crescent shape, relatively to the swing of the blade, so as to ensure a continuous scissors" action when cutting.

In accordance with a further feature, means may be associated with the movable knife blade to ensure that the knitted material is appropriately stretched and tensioned during the cutting operation. To this end the severing device may include a work tensioning plate which is disposed below the anvil and is movable with the knife blade to hold the work stretched across the anvil edge during the cutting operation. This plate will be the first to engage the knitted material as the blade swings and in so doing drag it across the anvil edge and stretch it there whilst the following knife blade slides over this edge to cut the tension material.

One form of an arrangement in accordance with this invention for severing the knitted product of a circular knitting machine will now be described by way of example in reference to the accompanying drawings, in which:

FIGURE 1 is a plan view of the arrangement,

FIGURE 2 is a cross section on the line IIII of FIGURE 1,

FIGURE 3 is a front view of the assembly, and

FIGURE 4 is a plan of the severing device per se.

The arrangement illustrated is assumed applied to a standard form of circular knitting machine, the main frame of which is diagrammatically indicated at 1, and in which the work 7, in this case assumed to be a continuously-knitted string of socks joined between the successive toes and welts by three or four courses of alginate thread, is taken down in the zone 2 at the side of the machine. The take-down means comprises a pair of grooved draw rollers 3 which are rotatable (by means which are not shown because they form no part of the present invention) between a pair of uprights 4 on a centrally apertured support plate 5. This latter is reciprocated in a circular are on the never rest principle (again by means which are not shown because they are of standard construction) on a fixed sleeve 6.

The plate 5 also serves for the mounting of a worksevering device, generally designated 8, below the rollers 3, and also disposed in this severing zone is a scanning device generally indicated 10, and means 9 controlled by this scanning device for operating the severing device. A control assembly 11 is provided on the machine to prepare the scanning device at required intervals for appropriate operation on the work. The means respectively designated 8 to 11 will be individually described in more detail below.

Sever-ing device 8 The basic components of this device are an anvil 12 and a cooperating knife blade 15. Anvil 12 is mounted on a frame 13, bolted to the support plate 5, and is provided with a part-circular and bevelled cutting edge 14. The knife blade 15 also has a bevelled and corresponding part-circular or crescent-shaped cutting edge 16. The blade 15 is pivoted on a pin 17, so that its edge 16 can be swung over the anvil edge 14 with a shearing or scissors action, and a spring 18 is provided beneath the head of the pivot pin to ensure proper cutting contact. The knife blade 15 is provided with a finger 19 which cooperates with a ramp 20 on the anvil to pilot the knife blade on to the anvil.

The blade 15 has a tailpiece 21 secured thereto through a stem 22 which also carries a work-tensioning plate 23. This plate is disposed below the anvil and has a turned-up, work-engaging lip 24.

The complete severing device, being secured to the support plate 5, shares the rotary-reciprocating movement of the latter such that, during a stroke in one direction in this reciprocation, a nose 25 on the tailpiece 21 will engage a mechanical abutment (see below) and be held whilst the anvil 12 continues to move in this direction with the work draped over the edge 14. In consequence the knife will, in effect, traverse over, so shearing across the work and the lip 24 will, at this time, pull the work taut from the lower side to assist the cutting operation.

It is further arranged that when the plate 5 returns the knife blade 15 will be positively swung back to its original position relatively to the anvil 12. For this purpose use is made of a tension spring 26 which is anchored at one end to a post 27 depending from the tailpiece 21, and at the other end to a post 28 on the support plate 5. An adjustable stop 29 on the tailpiece 21 determines the end of the return stroke of the knife, by reason of its abutment with a part of the frame of the machine.

Means 9 for operating the severing device As will be clear from the foregoing, the function of this means 9 is to interpose a mechanical abutment in the path of nose when a cutting action is to be performed. In the instance illustrated this abutment is represented by the lug 30 on a rockable arm 31 which extends horizontally and approximately tangentially over the support plate 5 and is pivoted on an arm upstanding from a bracket 32 bolted to the machine frame. The arm 31 is biassed by a tension spring 33 into a horizontal position, in which the lug 30 thereof is clear of the nose 25 of tailpiece 21, determined by an abutment 34 on bracket 32. The arm 31 is, however, connected by a coupling rod 35 to the movable armature 38 of a solenoid unit 36 and, in response to the energisation of the winding of this unit by the scanning device 10 (see below), the lug-carrying end of arm 31 will be pulled and inclined downwards, by an amount determined by an adjustable stop 37, to bringthe lug 30 into the path of tailpiece nose 25. In such a situation, as the support plate and rollers 3 carry out the stroke in one direction of their never rest motion, the nose 25, abutting against lug 30, will hold the knife blade 15 stationary to produce the above-described progressive shearing action across the width of the fabric. At the same time the spring 26 will be distended.

When, however, the travel of the support plate 5 is reversed, the nose 25 of the tailpiece 21 will be moved with it and will thereby leave the abutment lug 30, whereat the spring 26 will draw the knife blade 15 back to its starting position and re-set it relatively to the anvil.

Scanning device 10 This is represented by a photo-electric unit 41 and a projector 39 disposed in the severing zone 2. The projector 39 is, in fact, mounted on a bracket 40 secured to the frame of the machine and is levelled so that the axis of the beam therefrom will be thrown horizontally slightly below the anvil 12 and on to the photo-electric cell in unit 41. This photo-electric unit is electrically connected to a time relay (not shown) which in turn controls the energisation of the windings of solenoid 36.

The arrangement therefore is that, when a beam from a light source in projector 39 falls on the unit 41, it will excite the latter so as to produce energisation of the windings in solenoid unit 36, and hence a pull on rod 35, to move the abutment lug 30 into the path of the nose 25 of tailpiece 21. However, under normal conditions work 7 will be interposed in the path of the light beam and will be sufiiciently opaque to mask the unit 41, leaving solenoid 36 inoperative. Where, however, the work is light-permeable, as in the case of the sock-connecting loose courses of alginate thread referred to above, it will no longer mask the unit 41 and, as a consequence, the solenoid 36 will respond to initiate the shearing action.

It is important that the abutment lug 30 shall remain in knife-operating position for at least the whole of the stroke in one direction of support plate 5, and indeed it is often desirable that provision shall be made for repetition of this stroke, depending on the thickness of the yarn, the density of the knitted structure, and so on. It is the function of the relay referred to above to cater for these requirements and provide for a delay in the de-energisation of the winding of the solenoid 36 for a period found by experience or test to be desirable.

In operating the arrangement so far described it is, however, found advantageous not to have the light-source or projector 39 permanently illuminated during the whole of the operation of the knitting machine. Obviously this is technically wasteful, but beyond this it increases the hazard of inadvertent triggering of the severing device at unwanted times. Thus, for example, in the case of a string of socks, it could happen that the photoelectric cell might be excited by the light beam at parts of the sock other than the connecting loose courses, for example when there is a temporary interruption of the downward feed of the string during the knitting of the heel of a sock. For these reasons use is made of the control assembly 11 which will only switch on the light source in 39 immediately prior to the time of arrival of the loose courses at the cutting position.

Control assembly 11 As indicated above this control assembly is arranged to be operated in conjunction with the normal machine controls, i.e. in correlation with the other knitting functions of the machine which, in effect, determine the travel of the work. In a standard form of knitting machine the central control of these functions is exercised by the pattern drum which, inter alia, governs the travel of a pattern chain 42 which runs in a long endless loop down the front of the machine. In itself, it can be visualised that this chain could be equipped to operate the severing device directly, e.g. through appropriate cam means on the chain, but in practice it is found that the movement of such a chain is not sufficiently precise, for example due to the variations in length which can occur in varying temperature conditions, and changes in the work itself due to different yarn thicknesses and qualities, and so on. It is therefore used in the preferred arrangement now described merely to prepare the scanning unit and to allow the latter, as described, to exert the fine control of the severing time.

Thus, in the specific arrangement illustrated, the pattern chain 42 runs over a sprocket 43, which is loosely rotatable on a bracket 46 mounted at the front of the machine frame, and this chain has dogs 44 secured to the links thereof at appropriate spaced positions along its length. The chain is guided by the sprocket 43 so as to bring each succeeding dog 44 in turn into contact with the arm 45 of a bellcrank lever mounted on the bracket 46. The other arm 47 of this bellcrank lever is coupled through a link 48 to an arm 49 pivoted on a fixed bracket 50 of the machine, with its end part controlling the contact plunger 51 of a fixed switch 52.

This switch is included in the supply circuit to the light bulb in projector 39 so that, at regular intervals in the take-down of the work 7 and whilst the machine continues to knit in normal fashion, the light source of projector 39 is illuminated, and will trigger off the severing device 8, through scanning device and severing device operating means 9. The arm 49 can be re-set, and the switch contact broken, by an arm (not shown) connected to the armature 38.

It will be appreciated that the invention is not confined to the specific details which have been elaborated above. In particular, the severing device can take various forms.

We claim:

1. In a knitting machine having a work take-down means, an arrangement for severing individual lengths from a parent length of knitted material the knitted structure of which has different significant features, said arrangement comprising a severing device positioned adjacent said take-down means to act on said parent length, means for operating said severing device, and a detector device positioned adjacent the path of said parent length to scan the latter and adapted to actuate the severing device operating means in response to the detection of a significant feature of the knitted structure of the passing parent length.

2. A severing arrangement as claimed in claim 1, in which the detector device is a photo-electric system comprising a light source at one side of the path of said parent length and a photocell at the opposite side of this path.

3. In a knitting machine having a work take-down means, and a knitting control system, an arrangement for severing individual lengths from a parent length of knitted material the knitted structure of which has different significant features, said arrangement comprising a severing device positioned adjacent said take-down means to act on said parent length, means for operating said severing device, a detector unit comprising a light source and a photo-cell and positioned adjacent the path of said parent length to scan the latter and operatively connected to the severing device operating means so as to actuate the latter in response to the detection of a significant feature of the knitted strucure of he passing parent length, and a control assembly operable by said knitting control system to prepare said detector unit for operation.

4. In a knitting machine having a pair of take-down rollers, and means for reciprocating said roller pair over a circular arc, an arrangement for severing individual lengths from a parent length of knitted material the knitted structure of which has different significant features, said arrangement comprising a severing device mounted adjacent said rollers and having a first part reciprocable with said rollers and a cooperating second part movable relatively to said first part, abutment means movable into the path of said second part to cause a relative severing movement thereof, and a detector device positioned adjacent the path of said parent length to scan the latter and adapted to move said abutment means in response to the detection of a significant feature of the knitted structure of the passing parent .length.

5. In a knitting machine having a work take-down means, a knitting control system, an arrangement for severing individual lengths from a parent length of knitted material the knitted structure of which has different significant features, said arrangement comprising a reciprocable severing device positioned adjacent said take-down means to act on said parent length and having a first part and cooperating second part movable relatively to said first part, abutment means movable into the path of said second part to cause a relative severing movement thereof, a photoelectric system positioned adjacent the path of travel of said parent length to scan the latter, a control assembly operable by said knitting control system to energise said photoelectric system, and an electromagnetic device controlled by said photoelectric system to move said abutment means.

6. A severing arrangement as claimed in claim 5, in which the said first part of the severing device is an anvil and said second part is a knife blade pivotable relatively to said anvil, said knife blade and anvil having cooperating curved cutting edges.

7. A severing arrangement as claimed in claim 6, in which the severing device further includes a work-tensioning plate disposed at the opposite side of said anvil to said knife blade and movable with the latter.

References Cited by the Examiner UNITED STATES PATENTS 1,056,589 3/13 Ryan. 3,065,615 1'1/62 Abrams 66-l66 DONALD W. PARKER, Primary Examinerz RUSSELL C. MADER, Examiner. 

1. IN A KNITTING MACHINE HAVING A WORK TAKE-DOWN MEANS, AN ARRANGEMENT FOR SEVERING INDIVIDUAL LENGTHS FROM A PARENT LENGTH OF KNITTED MATERIAL THE KNITTED STRUCTURE OF WHICH HAS DIFFERENT SIGNIFICANT FEATURES, SAID ARRANGEMENT COMPRISING A SEVERING DEVICE POSITIONED ADJACENT SAID TAKE-DOWN MEANS TO ACT ON SAID PARENT LENGTH, MEANS FOR OPERATING SAID SEVERING DEVICE, AND A DETECTOR DEVICE POSITIONED ADJACENT THE PATH OF SAID PARENT 